X.] THE COMMON FROG. 



155 



14. There are no neck vertebras. 



15. No ribs join the sternum. 



16. There are no feathers or scales. 



17. There is no beak in the adult. 



18. There is no second (and inferior) larynx. 



19. There are not two ventricles to the heart. 



20. There is more than one aortic arch. 



21. The optic lobes are not lateral and depressed. 



22. The tongue is free behind. 



23. Development takes place through a metamor- 



phosis. 



24. Gills exist in the young. 



25. The ureters open into the oviducts. 



The Frog differs from the MAMMALS in that— 



1. Its blood is cold. 



2. The skull has no basi-occipital. 



3. It has a large paraphenoid. 



4. There is an iliac symphysis. 



5. The acetabula are closely applied together. 



6. The coccygeal region is formed by ossification 



of the sheath of the notochord. 



7. The tongue is free behind. 



8. The skin is devoid of hair. 



9. There is no distinct atlas vertebra. 



10. There are no neck vertebra. 



1 1. No ribs join the sternum. 



12. There are not two ventricles to the heart. 



13. There is more than one aortic arch 



14. There is no muscular partition between the 



chest and abdomen, i.e. no diaphragm. 



